This invention relates to a gas compressor apparatus using a compressor that produces discharge pulsation.
A compressor that compresses and delivers gas compresses the gas adiabatically, and consequently the delivered gas is hot. Because of this, problems arise if parts that are vulnerable to heat are present in devices to which the fluid (gas) is supplied, downstream of the compressor.
Known technology for solving this problem includes cooling the delivered fluid by injecting oil into the compression chamber of the compressor. With technology for cooling the delivered fluid by injecting oil into the compression chamber of the compressor, the temperature of the delivered fluid is lowered; however, because oil is mixed in with the fluid delivered from the compressor, if there are devices downstream of the compressor that are not oil-resistant or have poor resistance to oil, a device for removing the oil is necessary, and the overall construction becomes complicated.
Also, discharge pulsation from a compressor causes noise to be emitted from pipes connected to the compressor and is a major cause of compressor noise.
It is therefore an object of the present invention to provide a gas compressor apparatus in which the temperature of the delivered fluid is reduced without oil being mixed with the delivered fluid and in which discharge pulsation is reduced. Also, it is an object to provide a gas compressor apparatus that is reduced in size by integrating a delivered fluid cooling device and a discharge pulsation reducing device.
To achieve these and other objects, the invention essentially is a gas compressor apparatus that includes a compressor and a discharge pulsation reducing cooler, which is integral with the compressor. The discharge pulsation reducing cooler has a delivery passage, through which compressed gas flows, and a jacket, which covers the delivery passage. A cooling fluid flows between the jacket and the delivery passage.
By integrating the discharge pulsation reducing cooler with the compressor, not only can the compressed fluid be cooled, but the temperature of the compressor is prevented from rising due to heating of bearings and the like. Also, because discharge pulsation reduction and cooling can be achieved in the same space, the size of the gas compressor apparatus and the number of parts constituting the apparatus are reduced.
Also, the compressed fluid transfers heat to the cooling water and is cooled as it flows through the delivery passage of the discharge pulsation reducing cooler. Consequently, the temperature of the delivered fluid is lowered without mixing oil with the fluid.
In a second aspect of the invention, the gas compressor apparatus has, in the delivery passage covered by the jacket, an expansion chamber where the flow passage cross-sectional area increases. In the expansion chamber, pulsation is reduced efficiently. As a result, the discharge pulsation reducing cooler is relatively small and the gas compressor apparatus is relatively compact. Because the expansion chamber, which has a large pulsation-reducing effect, is covered with a jacket, the fluid is cooled by the cooling liquid even inside the expansion chamber. Consequently, the efficiency of heat exchange between the cooling liquid and the compressed fluid is high, and the delivered fluid is cooled efficiently. As a result, the discharge pulsation reducing cooler is relatively small and the gas compressor apparatus is relatively compact.
In a third aspect of the invention, the compressor apparatus has the expansion chamber in a downstream end of the delivery passage. In the delivery passage leading to the expansion chamber, because turbulence caused by pulsation arises, the efficiency of heat exchange between the delivered fluid and the cooling liquid inside the jacket is high, and the delivered fluid can be cooled efficiently. As a result, the discharge pulsation reducing cooler is relatively small and the gas compressor apparatus is relatively compact.
In a fourth aspect of the invention, the circumferential periphery of the compressor is covered by the discharge pulsation reducing cooler. In this case, because the path of propagation of noise emitted from the compressor proper is blocked by the discharge pulsation reducing cooler, noise is reduced.
In a fifth aspect of the invention, the discharge pulsation reducing cooler is provided in contact with a face of the compressor. In this case, piping connected to the compressor can be connected directly to the compressor, and piping connected to the discharge pulsation reducing cooler can be connected directly to the discharge pulsation reducing cooler. Consequently, compared to other variations, the piping layout and connection structure are simple. If the discharge pulsation reducing cooler is located on the face of the compressor from which the most noise is emitted, there is also a noise-reduction effect.
In a sixth aspect of the invention, the delivery passage covered by the jacket is curved so that the passage length inside the jacket is relatively long. By curving the delivery passage inside the jacket, extreme projections, which are undesirable when the apparatus is to be mounted in a vehicle, can be eliminated, and because, at the same time, discharge pulsation is reduced by the curved part, the discharge pulsation reducing cooler is relatively small, and the gas compressor apparatus is relatively compact. Further, because the heat exchange length over which the delivered fluid is cooled is relatively long, the heat transfer efficiency is increased without enlarging the device.
In a seventh aspect of the invention, the delivery passage covered by the jacket is curved so that compressed gas discharged from the compressor flows in a direction following a case of the compressor. In this case, because dead space around the compressor is used effectively, the gas compressor apparatus is relatively more compact.
In an eighth aspect of the invention, the discharge pulsation reducing cooler is made up of the delivery passage, which is covered by the jacket, and an expansion chamber, which is not covered by the jacket. The cross-sectional area of the expansion chamber is larger than that of the delivery passage. In this case, the jacket is not provided around the expansion chamber, and heat exchange is carried out only at the part of the delivery passage covered by the jacket. By not providing the jacket around the expansion chamber, where the flow passage cross-section is large, and by providing the jacket around the delivery passage, where the flow passage cross-section is smaller, the size of the discharge pulsation reducing cooler can be reduced, and the gas compressor apparatus can be more compact. By making the members forming the expansion chamber thick, it is possible to suppress noise emitted from the expansion chamber.
In a ninth aspect of the invention, the discharge pulsation reduction effect is increased by expansion chambers provided at both upstream and downstream ends of the delivery passage.
In a tenth aspect of the invention, to increase the discharge pulsation reduction effect with the same volume, the volume of the expansion chamber on the upstream side is made larger than that on the downstream side. By making the volume of the expansion chamber on the upstream side larger, it is possible to increase the reduction effect, particularly at lower frequencies of discharge pulsation.
In an eleventh aspect of the invention, to reduce discharge pulsation at a specific frequency at which discharge pulsation cannot be reduced just by changing the volume of the expansion chambers, an interfering muffler, which is effective in reducing discharge pulsation at the specific frequency, is built into the expansion chamber. By this, discharge pulsations over all frequencies can be reduced.
In a twelfth aspect of the invention, the compressor is a screw-type compressor, which compresses and delivers gas by rotation of a pair of mutually meshing rotors. In this case, because it is possible to commonize a passage through which a cooling liquid for cooling the compressed fluid flows and a passage through which a cooling liquid for suppressing operating noise of the compressor flows, the screw-type compressor apparatus can be made relatively compact.
In a thirteenth aspect of the invention, the screw-type compressor has a rotation transmission mechanism, for causing the pair of rotors to rotate in synchrony, and a lubricated box, which has a lubricant space in which the rotation transmission mechanism is housed and a lubricant is sealed. The lubricated box is covered by the jacket. In this case, the lubricant space and the delivered fluid, which in a screw-type compressor must be cooled, can be cooled using a common cooling liquid, and consequently the construction of the gas compressor apparatus can be simplified.
In a fourteenth aspect of the invention, the compressor apparatus has a construction wherein the cooling liquid flowing through the inside of the jacket is itself cooled. Consequently, the cooling of the delivered fluid and the compressor is stable.